2.  Torch model number

3.  Gas valve

4.  Cable/hose length

5.  Power cable type
     R - one-piece
     H - one-piece
     2 - two-piece
     N - two-piece

6.  Super-Flex cable

7.  Neck type
     RG - Rigid
     FX - Flex

Example torch:
CK17V-12-RSF RG - standard series, model 17, with gas valve, 12.5ft. one-piece power cable Super Flex, rigid neck

CK9-25-2 FX - standard series, model 9, 25ft., two-piece power cable, flex neck

Thread sizes for torch heads (collet body & back cap):
Models - 9, 20, 100, 110, 130, 200 and 230 - 5/16 - 24

Models - 17, 26, 18, 150, 210, 300 and 510 - 3/8 - 32